The 3-year-old dog named Mack dropped more than 10 feet to the bottom of the watery hole during a Sunday morning walk with his owner, Mattie Moore, who nearly fell in too.

Ms. Moore’s 911 call brought the fire department’s technical rescue team to Martin Luther King, Jr., Park, where a broken underground water pipe had eroded the soil to create an opening about 2 feet across on the surface but wider below.

“She was crying,” firefighter Michael Paveljack said, describing the frightened dog owner in the snowy park where she walks Mack every morning before sunrise.

Rescuers put plywood around the hole to stabilize the ground, then widened the gap enough for a person to fit through.

Mr. Paveljack climbed down a ladder, uncertain of how the 100-pound animal would react to him after standing in 18 inches of cold water for an hour.

“He was intimidating. He was a big dog,” said the firefighter, who once owned a German shepherd. “If he was mad, he could have attacked me. But he was just scared. He knew he was in trouble, and he wanted to get out of that hole as fast as possible.”

The plan was for Mr. Paveljack to lift the dog and bring him up the ladder, but the firefighter began to sink in the mud under the weight of the squirming, wet dog.

“I had water rolling over the top of my boots,” he said.

The firefighters up top lowered down the dog’s leash and rope for a makeshift harness and hoisted the dog up while Mr. Paveljack followed up the ladder, pushing from below.

“It was beautiful thing,” Ms. Moore told the Buffalo News. “He was wagging his tail, looking at all the people.”

Ms. Moore said that her leg had sunk into the hole but that she caught herself and crawled to safety. Her dog, she said, had run up from behind and toppled in.

Mack, she said, initially appeared to suffer only from a sore hip, but on Monday he was moving slowly and vomiting. She hoped to take him to a vet.

Meanwhile, a photo of Mack showing his appreciation with a canine kiss to Mr. Paveljack’s face has brought some heat from the rest of the firehouse.

“I’m catching a lot of stuff for the picture right now,” he said, laughing. “I just love dogs. I wanted to check him out, and he just happened to lick me.”